MXPA04007114A

MXPA04007114A - Medicament nnjection devive with axially displaceable lead screw.

Info

Publication number: MXPA04007114A
Application number: MXPA04007114A
Authority: MX
Inventors: Alistair Holdgate James
Original assignee: Dca Design Int Ltd
Priority date: 2002-01-25
Filing date: 2003-01-23
Publication date: 2005-03-31
Also published as: HUP0500033A2; CN1620317A; US7001360B2; ZA200405865B; KR20040096533A; EA200400976A1; BR0307102A; EP1471958A1; GB0201689D0; CA2474471A1; JP2005515034A; US20040087903A1; WO2003061736A1; EA006329B1; PL371423A1; HRP20040680A2

Abstract

The present invention relates to a medicament delivery device in which the medicament to be delivered is stored within a cartridge having a displaceable piston therein. The displaceable piston is driven to expel medicament by way of a lead screw (6) that is advanced and retracted by way of a suitable drive mechanism (14). A guideway (16) through which the lead screw travels is provided. However, in known devices the guideway is held in position by other components of the apparatus. Such devices can be complex to manufacture. Also they may require disassembly and reassembly when a cartridge is to be replaced. This is a disadvantage if the user, as is common amongst those with diabetes, is infirm or has impaired vision. A medicament delivery device is disclosed comprising a main housing (3), a threaded lead screw (6) having opposing flat surfaces, rotary driving means (14) having inner wall surfaces corresponding to the opposing flat surfaces of the lead screw and a guide housing (16) having an opening through which the threaded lead screw is received wherein the guide housing is permanently fixed to the main housing.

Description

DRUG INJECTION DEVICES WITH AXIAL DISPLACEMENT ADVANCE SCREW The present invention relates to a drug delivery device, for example, a device for injection or infusion. Especially, this invention has particular but not exclusive application in a drug delivery device wherein the drug to be delivered is stored in a replaceable cartridge having a piston that can travel there. Such devices are used, for example, commonly in the case of diabetic patients for insulin administration. In such devices, the displaceable piston is urged to cause the expulsion of a drug by a lead screw or other type of pistons. The advancing screw can be advanced and retracted conveniently through an appropriate drive mechanism. It is known to provide a drive mechanism in which the rotary movement of a motor or other suitable drive is transformed into linear movement of the feed screw. It is known to provide a guide or guide housing through which the lead screw is displaced. However, in known devices, the guide is maintained in the desired operating position through other components of the apparatus. For example, in document E'P 0X4"3 8" 9"5 is ¾ívuTga att? device for infusion. The device comprises a frame having a cavity shaped there. A first part of the cavity serves as a mounting support for a replaceable drug cartridge. A rotary impeller sleeve is located in a second part of the cavity. The feed screw is adapted to move through the impeller sleeve. The threaded lead screw has flat, opposite surfaces. The inner part of the carrier sleeve fits in the shape of the feed screw to prevent rotation of the feed screw independently of the driver sleeve. The guide takes the form of a threaded nut which is threaded in the lead screw. The nut is located in a specially formed recess of the frame cavity to prevent rotation of the nut. An axial movement of the nut is avoided thanks to the fact that in a spindle the nut is trapped between on one side the frame and on the other hand at one end of the drug cartridge cylinder. In use, the impeller sleeve carries the threaded rod that moves forward as a screw moves through the nut or guide held in the frame. Such devices are complex in their manufacture. The shaped cavity requires a suitable tolerance both to receive the impeller sleeve and to provide a locating recess with a "OTrm" a ~ a ~ d "e_caa" dci "for the nut that acts as a guide. In addition, proper placement of the cartridge barrel is required to prevent the nut from loosening and proper placement of the nut must be ensured each time a drug cartridge is replaced. Said disarming and reassembling when a cartridge must be replaced is a disadvge if the user, as is common among diabetics, suffers from disability or has impaired vision. The use of guide means is also known in drug delivery devices where the linear displacement of a driving device directly or indirectly causes a linear movement of a lead screw along a longitudinal axis to cause the assortment of a drug In devices of this type, the displacement of the advancing screw is limited by a displaceable guide means, the displacement of the guide means corresponding to a dosage selected by a user. In such an injector, a lead screw having flat opposite sides is located again within an impeller. The impeller interacts with a nut. The nut has an opening with a suitable shape for receiving the lead screw in order to prevent the lead screw from rotating relative to the nut. The nut has grooves that engage in a free-standing groove-pO-rcxon ~~ of ~ boom body. A retainer is securely mounted releasably on the body to hold a drug cartridge in place. When the cartridge is absent, the retraction nut and the feed screw can freely rotate and retract in the body. However, a friction ring is required to keep the tueca captive in the impeller to prevent it from going down the lead screw when changing a cartridge. There is a need for a drug delivery device that eliminates or at least reduces these problems.

In accordance with the present invention, a drug delivery device comprises a main frame, a threaded lead screw having opposite flat surfaces, a rotary drive device having internal wall surfaces corresponding to opposite flat surfaces of the lead screw and a guide frame having an opening through which the threaded lead screw is received wherein the guide frame is permanently fixed on the main frame. This has the advantage in that the guide frame can not be displaced relative to the lead screw. Preferably, the guide frame is formed integrally with the main frame. Preferably, the main frame comprises two half-frames and a one-piece frame unit in which it is "formed: the guide frame." Preferably, a motor and several rotary drive means are brought from the frame unit of the frame. The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows relatively schematically a drug delivery device in accordance with the present invention with elements of the main frame shown in phantom lines, Figure 2 shows a view similar to the view of the figure 1 with most of the main frame removed for reasons of clarity; Figure 3 shows a view similar to the view of the figure 2 with the advancing screw in an advanced position; Figure 4 shows a side view corresponding to Figures 1 and 2, again with most of the main frame removed for clarity; Figure 5 shows a side view similar to Figure 4 with the advancing screw in an advanced position in line with Figure 3; and Figure 6 shows a frame unit in which a guide frame has been formed. With reference to Figures 1 to 5, generally, and with reference to Figure 1 in particular, there is shown a drug delivery device 2 comprising ü ~ ñ main frame 3 within which are located numerous components including a cartridge replaceable drug 4, a plunger in the form of a lead screw 6 for driving a piston 5 within the drug cartridge 4 to cause, in use, the drug to be expelled and a driving device 8 for driving the plunger. A power source, for example, batteries 18 may also be provided to power the drive device 8. The drug delivery device 2 may also include a deployment 10 through which certain information relevant to the operation and / or use may be communicated. of the drug delivery device to a user. A central control unit or microprocessor (not illustrated) can also be provided to control the operation of the drug delivery device 2 and to determine the nature of the information that appears in the display 10. The plunger and the driving means are shown in FIG. more clearly in Figures 2 to 5. A motor 12 is connected to drive the advancing screw 6 or plunger through numerous rotary drive means, for example, drive train elements 14, 14 ', placed to form a train driving. The advancing screw 6 typically has a generally circular section even when it has flat sides arranged in an opposite manner that are aligned with the CTOTT relative to the advancing screw. A screw thread is carried by the remaining sides of the feed screw 6. The feed screw 6 is positioned to operate through a guide frame 16. The guide frame 16 is formed as part of the main frame 3. The frame guide 16 includes an opening through which the feed screw 6 passes. The opening of the guide frame 16 is configured for the cross section of the feed screw 6 to prevent a relative rotation between the feed screw 6 and the frame guide 16. A final element 14 'in the gear train is provided with a threaded bore through which the feed screw 6 also passes. The end element of the gear train 14' can rotate relative to the feed screw 6. When it is driven by the other elements 14 in the drive train, the rotation of the end gear train element 14 'in the drive train causes the feed screw 6 that can not rotate due to the guide frame to advance. In this way, by controlling the direction of rotation of the end gear train element 14 ', the feed screw 6 can either advance through the replaceable drug cartridge 4 to deliver drug or it can be retracted to facilitate insertion Subsequent to a replacement drug cartridge 4. The main frame 3 is usually formed in the form of two opposing half-frames .. The guide frame 16 can be formed integrally with one of the half-frames. 16 can be formed in portions in each half frame to form a complete guide frame 16 when the main frame 3 is assembled. As an additional alternative, the guide frame 16 can be fixed on one of the half frames before the assembly of the drug delivery device 2. As a further alternative, in which the guide frame is formed integrally with the main frame, this part of the main frame can be formed as a separate unit 20 (figure 6) for placement between two opposite half frames, ie the main frame 3 comprises the two opposite half frames and the guide frame unit 20, the remaining components standing in relation to these elements of the main frame. For example, the drive train elements 14, 14 'and the motor 12 can be mounted comfortably on the guide frame unit 20.

Claims

CLAIMS A drug delivery device comprising a main frame, a threaded lead screw having opposite flat surfaces, a rotary drive device, having internal wall surfaces corresponding to the opposite flat surfaces of the feed screw and a frame of guide having an opening through which the threaded feed screw is received wherein the guide frame is permanently fixed on the main frame. A drug delivery device according to claim 1, wherein the guide frame is formed integrally with the main frame. A drug delivery device according to claim 2, wherein the main frame comprises two half frames and a guide frame unit where the guide frame is formed. A drug delivery device according to claim 3, wherein a motor and several rotary drive means are ported from the guide frame unit. A drug delivery device substantially cOnfoxm dHd with to here described with reference to the accompanying drawings and in accordance with that illustrated in said drawings. 5 10 fifteen "2'5-